The present invention relates to an optical waveguide network for crossing-free switching of a guided signal from any input to any output and consisting of n waveguides disposed optically parallel to one another and located on a substrate and of a plurality of pairs of electrodes.
In addition to simple branching systems, optical communications techniques with guided light waves also require switchable branching networks. These networks can be built up on a basic substrate in the form of integrated optical circuits.
In an article by H. F. Taylor - "Design of Optical Circuits", which appeared in NELC TR 1913 AD 779847 Report, April 1974, a network is illustrated in which the light is transferred from waveguide to waveguide in a switching element along a defined transfer path. The transfer length over which a specific waveguide mode transfers completely from one waveguide to the other with a given waveguide separation and a given waveguide breadth depends upon the refractive indices of the switch components. With this known switching arrangement, the refractive indices of an electro-optical material are controlled by special electrode structures through which waveguides are induced while the wave guidance only takes place here in one layer plane.
Consequently, to build a network with n inputs and n outputs n(n-1)/2 switching elements are needed in order to minimize the problems of cross-talk.